Page 345 - Design for Six Sigma a Roadmap for Product Development

Theory of Inventive Problem Solving (TRIZ) 315

Functional improvement methods are the methods to improve the
delivery of useful functions and to eliminate or contain harmful func-
tions. Functional improvement methods are derived from TRIZ ’76
standard solutions compiled by G.S. Altshuller and his associates
between 1975 and 1985 (Domb et al. 1999). We will describe the func-
tional improvement methods in the following two categories: the meth-
ods to improve useful functions and the methods to eliminate or
contain harmful functions.

9.6.1 Methods to improve useful functions
If a useful function is not delivered or is not delivered properly, then
there are two main reasons:
1. There are some element(s) missing in the subject-action-object
model. The most frequently missing elements are the subject and
action. In this case the function will not be delivered at all. To
resolve this situation, we need to supply the missing elements in
the subject-action-object model.
2. Some elements(s) in the subject-action-object model are not working
properly, it could be the object, the field, or the subject, or a combi-
nation of them. In this case the useful function will not be ade-
quately delivered. To resolve this situation, we need to improve the
elements which are not working properly.

We will discuss several frequently used methods as follows.

Method 1: Fill the missing elements
in a subject-action-object model
The most frequently missing elements in a subject-action-object model
are subject and action, that is, the current situation is:

Object

We need to find an action, or field, and an subject to complete the func-
tion model:

Action
Subject Object
Field

Example 9.13 A liquid contains vapor bubbles. The desired effect is to sep-
arate the bubbles from the liquid, however, that effect is not happening. The
subject-action-object model for the actual situation is as follows: